Numerical Simulation of Large Angle-of-Attack Separated Flows Over Airfoils of HAWT Rotors

The characteristics of an airfoil at stall conditions determine the performance of stall regulated HAWT rotors and constitute the base of the flutter estimation of blades. This paper presents a numerical simulation of large-angle-of-attack separated flows over airfoils for stall regulated HAWT rotors. The two dimensional Navier-Stokes equations in a body-fitted system is adopted, and the C-type grid system is generated, applying CAD surface structure technology and multi-block grid technology. The two-dimensional flow is modelled as turbulent and incompressible. Numerical solutions are obtained using the RANS scheme with a double equation model of RNG kappa-epsilon. Numerical simulation of flow over FFA-W3-211 airfoils is given, and the accuracy of the numerical results of lift and drag coefficients is compared with wind tunnel test data at angles of attack from-6 degrees to 60 degrees. The comparison between them shows good agreement.